[llvm] [DirectX] Add DebugInfo pass (PR #191254)

[Justin Bogner via llvm-commits]

https://github.com/bogner commented:

This all looks reasonable but I think the naming is too generic. Should we call these things DXILDebugInfo or DirectXDebugInfo or something to that effect?

https://github.com/llvm/llvm-project/pull/191254